1. Field of the Invention
The present invention relates to a backlight for a liquid crystal display (LCD), and more particularly, to a lens configuration for increased light distribution uniformity in an LCD backlight.
2. Description of the Related Art
The active parts of liquid crystal display (LCD) panels, such as polarizers, liquid crystal layers, indium tin oxide electrodes, supports, etc., are relatively thin. However, standard designs for direct or edge-lit backlight assemblies for LCDs are bulky, and need to be custom designed for each LCD panel size. In fact, most of the physical volume of a typical/conventional backlit LCD panel is occupied by the backlight assembly itself.
The reason for the bulkiness of the backlight assembly is the space required for light originating at a few discrete points in the assembly, to be thoroughly randomized, or diffused, so that the liquid crystal (LC) layer is illuminated by a uniformly distributed flux of light. Due to surface size constraints, only a small number of LEDs can be used for backlighting systems. The LEDs need to illuminate an entire LCD. A bulky diffuser is thus required to make the intensity of the light from the small number of LEDs uniform across the LC screen.
The number of LEDs used for backlighting LCD systems may be increased. However, a larger number of LEDs leads to higher cost, increased energy consumption, and poses reliability problems. Moreover, regardless how many LEDs are used, each LED creates a highly non-uniform local lighting profile, as the intensity of light generated by an LED decreases as a function of distance from the LED.
Disclosed embodiments of this application address these and other issues by utilizing lens that are configured to increase uniformity of light distribution in an LCD backlight arrangement.